Overclock a CPU and 2-3 GPUs and not burn the house down

[jtk700cln]

Hey folks, 

 

A few things have been really confusing me about my own computer build.  Its not the mathematics of the power consumption, its the reality of

 

being able to actually overclock a cpu and 2-3 gpus, and not burn my entire house down lol.   

 

 

Im building my own pc, trying to be really careful with the specs, research on power consumption, overclocking, etc, and Im really confused as to how other people are getting away with overclocking/mining pcs (4 gpus??), considering the reality of power consumption with the newest cpus and gpus, and standard outlets in a home.  

 

 

Case and point example of theoretical overclocking--numbers from gamers nexus and elsewhere.  

 

ryzen 3970 --overclocked --700 Watts

nvidia 3090 founds (or aib) --overclocked-- 550Wx2- 1100 Watts

 

These numbers alone take me over what any standard power supply could handle.  Add in fans, pump, ram, storage, and you are looking at 2200 Watts out of the box.   One more gpu and your looking at 2671 Watts!!

 

This means I would need to get two power supplies.  Great-thats not easy--even throwing two into an enthoo elite case, your compromising some of the space you could use for rads, etc.   Oh and then these power supplies need to plug in somewhere.   Problem is most outlets in a home are 15 AMP circuits.  Some simple math on this:

 

15 Amps (standard home outlet) = 120*15 Watts Non Peak. Or 1800 Watts.
Of which, 80% can be in use for lengthy periods of time. 

Even a 20 Amp circuit would only cover 2400 Watts at load, and it cant do this for extended periods of time.    

 

All this means I would need:

 two power supplies,

two surge protectors running to two different outlets......long story short, a whole lot of extra gear, and money, on top of the additional cost of watercooling.  To a point, it all seems a bit ridiculous to me.    

 

 

To put things in perspective, without overclocking, 

ryzen 3970 --not overclocked --500 Watts

nvidia 3090 founds (or aib) -not overclocked-- 550Wx2- 350 Watts

 

Totals after added in parts: roughly 1400 Watts.

This is about what a 15 Amp circuit can handle, along with a 1600 w power supply from say Corsair.   

 

 

It just makes me wonder, is 

overclocking really even worth it?  in the same vane, is watercooling even worth it if you are not overclocking? 

 

Would it make more sense to just simply my whole setup, use some aio coolers, not overclock, and call it a day?  

 

 

 

Would love to get some perspective on this.  Im a vfx artist, and I will be abusing this hardware.  But I frankly feel like I might be going down a rabbithole.  .....I wanted to overclock and use water cooling in the first place for the same reason as everybody, to avoid throttling my performance, but the truth is the more I look at the numbers the more I am unsure of its feasibility. I will be using Clarisse (cpu) and Redshift (gpu) all of the time, and I was worried about throttling my parts under full load..........

 

 

thanks all!!!  and definitely let me know if there is something terrible about my math!!!!!!

 

 

 

 

 

 

[Mateyyy]

3 minutes ago, jtk700cln said:

ryzen 3970 --overclocked --700 Watts

nvidia 3090 founds (or aib) --overclocked-- 550Wx2- 1100 Watts

ryzen 3970 --not overclocked --500 Watts

..where did you get those numbers from?

Also, what do you plan on using a 3970X and two RTX 3090s for?

[Dedayog]

You could have another line added to the house, you can easily afford it with the money you're spending on that PC.

 

Everything has balance.  It's like whining about the insurance and gas for a Ferrari.

[Moonzy]

3 minutes ago, jtk700cln said:

ryzen 3970 --overclocked --700 Watts

nvidia 3090 founds (or aib) --overclocked-- 550Wx2- 1100 Watts

 

To put things in perspective, without overclocking, 

ryzen 3970 --not overclocked --500 Watts

where did you pull these numbers from?

3970x takes 500W at stock? that's probably false, or i'll be very surprised

im surprised if it takes more than 200W at stock.

 

4 minutes ago, jtk700cln said:

Im really confused as to how other people are getting away with overclocking/mining pcs (4 gpus??)

miners will undervolt their GPU, to make them run more efficient

so the power consumption is low

 

my 4 GPU + 3900x rig pulls 800W from the wall when mining

[jtk700cln]

thank you both.  I will be using this pc for professional purposes as a vfx artist.  and thats a good point on the addition of a second line.  I know that fridges and ac units often run on 40 Amp outlets.  Perhaps thats the way to go.  

[jtk700cln]

2 minutes ago, Moonzy said:

where did you pull these numbers from?

3970x takes 500W at stock? that's probably false, or i'll be very surprised

im surprised if it takes more than 200W at stock.

 

miners will undervolt their GPU, to make them run more efficient

so the power consumption is low

 

my 4 GPU + 3900x rig pulls 800W from the wall when mining

Well i pulled it from here?

https://www.guru3d.com/articles-pages/amd-ryzen-threadripper-3970x-review,5.html

 

I figured this was fairly reliable?

[Dedayog]

2 minutes ago, jtk700cln said:

thank you both.  I will be using this pc for professional purposes as a vfx artist.  and thats a good point on the addition of a second line.  I know that fridges and ac units often run on 40 Amp outlets.  Perhaps thats the way to go.  

Professionals don't usually OC their components as they prefer stability over a few more %'s of performance.

 

[jtk700cln]

2 minutes ago, Dedayog said:

Professionals don't usually OC their components as they prefer stability over a few more %'s of performance.

 

Good point.  Perhaps I just romanticized the performance gains of watercooling, having never really done it before.  Is watercooling of any real benefit if you are not overclocking?

[Electronics Wizardy]

5 minutes ago, jtk700cln said:

thank you both.  I will be using this pc for professional purposes as a vfx artist.  and thats a good point on the addition of a second line.  I know that fridges and ac units often run on 40 Amp outlets.  Perhaps thats the way to go.  

If your gonna do a new outlet, do a 240v outlet. Might as well,

 

 

That power usage you showed is a full system load, so it included gpus, storage, ram, motherboard, and psu loss.

[Moonzy]

4 minutes ago, jtk700cln said:

Well i pulled it from here?

https://www.guru3d.com/articles-pages/amd-ryzen-threadripper-3970x-review,5.html

 

I figured this was fairly reliable?

-stares at it-

full system load, 435W, so i assume the CPU takes around 380W...? that's really high

the 3900x number in the chart checks out from my experience.

[Electronics Wizardy]

Just now, jtk700cln said:

Good point.  Perhaps I just romanticized the performance gains of watercooling, having never really done it before.  Is watercooling of any real benefit if you are not overclocking?

If your not gonna oc I wouldn't bother, the extra temps won't affect anything much, and those parts should be able to be cooled on air cooling fine stock with good airflow.

 

Also water cooling is pretty pricy, and require much more matience and is more likely to fail.

 

Also OCing doesn't really get you that much, esp with newer parts. The days of getting 50% ocs are over, and a 5-10% oc is much more realistic, and probalby not worth it.

[igormp]

Some places have 220 mains voltage. Here I have both 10A and 20A outlets, which means a max of 2200W or 4400W.

 

Another point is, for people running on two or even 3 PSUs, those are usually used with different power lines, so it's 15A for each using your own example.

[jtk700cln]

1 minute ago, Moonzy said:

-stares at it-

full system load, 435W, so i assume the CPU takes around 380W...? that's really high

the 3900x number in the chart checks out from my experience.

Ooof, foot in mouth--terrible reading on my part.   

[Moonzy]

6 minutes ago, jtk700cln said:

Ooof, foot in mouth--terrible reading on my part.   

no you're not too far off

but like, zen2 works best when undervolted if you ask me

 

i undervolted my 3900x, temps dropped 15c, power consumption dropped 25-30%, i could keep my cores at 4GHZ, which is the stock all core clock when running full load, so i lost no multithreaded perf, but you do lose single core boost

 

as for GPU, same thing, i dropped my 2070 to 70%, clock and mem speed did not change, nor is it unstable. (though your mileage may vary but you get my point)

[jtk700cln]

3 minutes ago, igormp said:

Some places have 220 mains voltage. Here I have both 10A and 20A outlets, which means a max of 2200W or 4400W.

 

Another point is, for people running on two or even 3 PSUs, those are usually used with different power lines, so it's 15A for each using your own example.

Apologies but a bit confused on this.  A 10A outlet should only be 1200W right?  And this should only be running at 80%?

 

14 minutes ago, Electronics Wizardy said:

If your gonna do a new outlet, do a 240v outlet. Might as well,

 

 

That power usage you showed is a full system load, so it included gpus, storage, ram, motherboard, and psu loss.

 240v to 30 Amp would definitely cover an overclocked cpu and 2-3gpus.

To your second point, my calculations seem high then, but are they that off really?  Charts as they are would seem to imply even with a second gpu, I wouldnt go over 1000W.  However they dont indicate overclocked gpus though.  Is a 1600W power supply really enough for 1 cpu and two overclocked gpus?

 

1 minute ago, Moonzy said:

no you're not too far off

but like, zen2 works best when undervolted if you ask me

 

i undervolted my 3900x, temps dropped 15c, power consumption dropped 25-30%, i could keep my cores at 4GHZ, which is the stock all core clock when running full load, so i lost no multithreaded perf

 

as for GPU, same thing, i dropped my 2070 to 70%, clock and mem speed did not change, nor is it unstable. (though your mileage may vary but you get my point)

Ive never even heard of undervolting, hugely informative.  Just doing some reading, there seem to be differing opinions on whether or not you can undervolt and still retain performance though.  I guess I would have to see for myself.

 

Thanks for all the tips so far.  Trying to process and not run in circles here.  

[Electronics Wizardy]

1 minute ago, jtk700cln said:

To your second point, my calculations seem high then, but are they that off really?  Charts as they are would seem to imply even with a second gpu, I wouldnt go over 1000W.  However they dont indicate overclocked gpus though.  Is a 1600W power supply really enough for 1 cpu and two overclocked gpus?

Wait for the 3090's first. we don't know their power draw yet.

 

But Id guess a 1600W psu will be plenty for those parts, and even with a mild oc. I wouldn't do a crazy oc, esp for a work machine

 

2 minutes ago, jtk700cln said:

Apologies but a bit confused on this.  A 10A outlet should only be 1200W right?  And this should only be running at 80%?

Depends on your mains voltage. Im assuming you have 120v outlets. In that case, make sure your wiring and breakers are made for 15a(common), 20a(found on some circuits). Then check what else is on that circuit. Then you want to use about 80% of that max, don't use 1800w on a 15a circuit continously.

[igormp]

7 minutes ago, jtk700cln said:

Apologies but a bit confused on this.  A 10A outlet should only be 1200W right?  And this should only be running at 80%?

I have 220v mains voltage, that's what I meant.

[dalekphalm]

It sounds like the OP @jtk700cln is from North America and is using 120V mains voltage.

 

For most NA houses, your house is wired for 2 voltages: 120V and 240V (it depends a bit, but normally your house is wired from the mains via 2x 120V lines, which are combined in the main circuit breaker of the house to get 240V - if you need a circuit with 120V, you pull from one of the 2 main lines. If you need 240V, you pull from both. The Circuit Box is already designed with this in mind, and terminals alternate between Mains1 and Mains2, so a double-thickness 240V breaker pairs the 2 lines together).

 

Anyway, in short, you probably don't actually need to run that much juice - as others have said, with Mining, you want to undervolt, if anything, because instability means crashes, and crashes means no mining.

 

Aside from that, even if you did need more power, there's a correct way about doing it (and what kind of equipment you're running also matters). For example, you really don't want to run a 240V circuit for something like this unless absolutely necessary. Not every device may come with a switching PSU (switching meaning it can run on both 120V and 240V). Also, the 240V plug is totally different from a 120V plug, so all your devices will need adapters (or you're wiring a plug from one standard to another, which is not really ideal). Adapters do exist though.

 

At 120V, standard is 15A (NEMA 5-15P for the plugs and 5-15R for the sockets (receptacles)). You also have 20A with the 5-20P/R. The 5-15P plug will connect to a 5-20R socket without conversion, meaning all your power cables will work fine. Lastly there's 30A with the 5-30P/R - but these have different style plugs and require an adapter.

 

120V 15A = 1800W

120V 20A = 2400W

120V 30A = 3600W

 

Minus 20% for safety, and that's your sustained load on each.

 

You can do 240V at numerous Amps as well - but adapters will definitely be required.

 

Anyway, all in all, I'd drop the idea of overclocking entirely, and try and design a PC that fits within 1200W or less. Houses in NA are wired with many different circuits, so just find a socket with nothing else on the same circuit, and dedicate that to your PC if you're running close to the 1200W.

 

 

[GDRRiley]

some of How I'm able to run 2-3PC plus some servers is my room has 1 20A and 2 15A 120V circuits

I really only have 35A free after lights and other things on 1 of the 15A circuits

which means I can do about 3500W of power draw

 

most newer houses and houses with AC should have 200A but often older have 100A

 

[dalekphalm]

46 minutes ago, GDRRiley said:

some of How I'm able to run 2-3PC plus some servers is my room has 1 20A and 2 15A 120V circuits

I really only have 35A free after lights and other things on 1 of the 15A circuits

which means I can do about 3500W of power draw

 

most newer houses and houses with AC should have 200A but often older have 100A

 

Yep anything built in the last 20 or 30 years should have 200A to the house. Older houses can be upgraded of course, but that normally means new lines (or a second) to the home, plus a new breaker box. 

[GDRRiley]

7 minutes ago, dalekphalm said:

Yep anything built in the last 20 or 30 years should have 200A to the house. Older houses can be upgraded of course, but that normally means new lines (or a second) to the home, plus a new breaker box. 

yep its a 4-5k USD upgrade.

[Moonzy]

5 hours ago, jtk700cln said:

never even heard of undervolting, hugely informative.  Just doing some reading, there seem to be differing opinions on whether or not you can undervolt and still retain performance though.  I guess I would have to see for myself.

Depends on your luck, so far I've been pretty lucky